I see it going 2 ways.
If some random serial killer, mob goon, or just otherwise irredeemable piece of filth dies then hooray.
If some poor starving child, or innocent person dies, well that is a shame and I would feel bad...

Regardless of who died, I would still likely donate a portion of it to charity (because really... who the hell needs $100 million?) and it would likely save more lives. I figure one casualty to save many others is worthwhile.

I would open it. Even if someone's going to die, I'd rather a happy sustainable life be lived out by me and my non-existant kids and grandkids, than save the life of one person. One life of a stranger versus at least 5 including me (and if we're going by plural) of people I'd hold close to me? I'd choose the 4 closest to me, and myself every time.

I wonder if people realize they could probably not make 100M in their lifetime
To do that you would need to invest and be smart with money
or win the lotto...

Then again in reality people would just slam the door on the guys face, not open the door, call the cops, get right out mad or think it was a prank, and finally for the really cool people, invite the guy in for a cup of coffee or tea and then become friends.

I don't actually think there would be a single person that gullible to take the man seriously

If I could ensure that the person who would die would be me, then I would open it.
But not before giving it to my family first.
I would happily give my life to make sure that my family would live safely.

If I don't open it...then someone else will surely will. So of course I'll open it.

Edit: Realistically won't happen. If it did, it will be stupid. I thought of simulating the experience in my mind about uhh 5 times? While doing so, I thought of what I will really do. I ended up reevaluating my decision and chose that I will not open it if it really happened to me. Life doesn't work that way. I will most likely ask questions as well.

Edit: If for some reason that I declined the box...and someone else accepted and I ended up dying because of the mistake of not accepting the box when I had the chance, I wouldn't be mad or argue about it. It's human nature to make risks that better your own life.

Edit:I will probably find a loop hole....say, take the box....give it to a friend and/or stranger and say, "Hey, someone told me to give this box to you. It was a gift to help repay for how you helped him. He couldn't give it to you personally because he had some important business to attend to and couldn't find any time to give you his gratitude and thanks. He also stated that you open it once you receive it."

After that, I will see what happens. If it's true that the person got 100 million. That person will most likely react with, "Holy **** look at all this money! It must be worth a fortune. How much money do you think is in it?" Me: "I don't know....(but I do know)...say, how about we split the money?" Stranger/Friend:"Well....you did bring it to me...and you could have easily opened it yourself and got all the money....OK, deal." Me:"Sweet! May I have your name and address?Stranger/Friend:" Of course...here."Me:" Alrighty then, lets plan for our prosperous future shall we?" And thus we become friends

Edit: If that person decides to run away...I just call the cops and say this person is in possession of a large sum of money in which I think he/she obtained by illegal means.

Edit: The most likely candidate to fool will be a poor or homeless person. More on the homeless side. Being homeless, he/she doesn't know what to do with the money and will most likely depend and trust you since you gave him/her the box.

What factors establish value to a human life? I hate the cliche of "human life is priceless." That is BS. The value of a starving child in Africa is lesser than compared to that of an affluent, nourished, and educated Westerner, and I reason that from the value of transferable organs/tissue, education level, agency/capability/merit, anticipated lifetimes earnings, net worth/convertible liquid assets/liabilities, and societal perceptions (fellow countrymen prioritizing the lives of compatriots). There are of course other unaccounted factors and risks, it would be unfortunate, even devastating if the life of a prominent scientist were affected (along with individuals with critical occupations [although perhaps the amount granted to their research or groundbreaking discovery may be factored into their worth]). That is the worse case, second to that would be those closest.

I am cynical to the commitment of people and surmise that if offered $100M, many would immediately renege their declaration to refrain than commit to it. I could be be pleasantly surprised too. I hate money and how currency has adversely and forcefully integrated many to become dependent on it to live, contrarily I would open that box or push that button. After all, it is only the life of one person, no matter how numerically and highly improbable it would affect me.